click below
click below
Normal Size Small Size show me how
Physics Unit 8
Electricity & Magnetism
Term | Definition |
---|---|
electricity | a general term for electrical phenomena |
electrostatics | the study of electric charge at rest |
Conservation of Charge | electric charge is neither created or destroyed; the total charge before an interactions equals the total charge after |
Coulomb's Law | the relationship among electrical force, charge, & distance; opposites attract, likes repel |
coulomb | the SI unit of electric charge |
conductor | any material that has free charged particles that easily flow through it when an electrical force acts on them |
insulator | a material that does not contain free charged particles and through which charge does not easily flow |
semiconductor | a material with properties that fall between those of a conductor and an insulator and whose resistance can be affected by adding impurities |
superconductor | a material that is a perfect conductor with zero resistance to the flow of electric charge |
charging by contact | the transfer of electric charges between objects by rubbing or simple touching |
charging by induction | the redistribution of electric charges in and on objects caused by the electrical influence of a charged object close by, but not in contact |
electrically polarized | the term applied to an atom or molecule in which the charges are aligned so that one side has a slight excess of positive charge and the other side a slight excess of negative charge |
electric field | electrical force per unit of charge; a storehouse of electric energy; operates under the inverse square law |
electric potential energy | the energy a charged object possesses by virtue of its location in an electric field |
electric potential | the electric potential energy per unit of charge; measured in volts called voltage |
capacitor | an electric device that stores electric charge and energy |
potential difference | the difference in electric potential between two points; measured in volts |
electric current | the flow of electric charge that transports energy from one place to another; measured in amperes |
electrical resistance | the property of a material that resists electric current; measured in ohms |
Ohm's Law | the current in a circuit varies in direct proportion to the potential difference or voltage across the circuit and inversely with the circuit's resistance |
direct current (dc) | electrically charged particles flowing in one direction only |
alternating current (ac) | electrically charged particles that repeatedly reverse direction, vibrating about relatively fixed positions |
electric power | the rate of energy transfer, or the rate of doing work; the amount of energy per unit time; the product of current and voltage |
series circuit | an electric circuit in which electrical devices are connected along a single loop of wire such that the same current is in each device |
parallel circuit | an electric circuit in which electrical devices are connected in such a way that the same voltage acts across each one, and any single one completes the circuit independently of all others |
magnetic force | 1)attraction of unlike magnetic poles and repulsion of like magnetic poles; 2)the deflecting force between a magnetic field and a moving charged particle |
magnetic field | the region of magnetic influence around a magnetic pole or a moving charged particle |
magnetic domains | clustered regions of aligned magnetic atoms |
electromagnet | a magnet whose field is produced by an electric current |
cosmic rays | high speed particles that travel throughout the universe |
electromagnetic conduction | the creation of voltage when a magnetic field changes with time; a change in the magnetic field of a closed loop induces a voltage |
Faraday's Law | the induced voltage in a coil is proportional to the product of its number of loops, the cross-sectional area of each loop, and the rate at which the magnetic field changes within these loops |
generator | an electromagnetic induction device that produces electric current by rotating a coil within a stationary magnetic field; converts mechanical energy to electric enegy |
transformer | a device for transferring electric power from one coil of wire to another for the purpose of transforming one value of voltage into another |
Maxwell's Counterpart to Faraday's Law | a magnetic field is created in any region of space in which an electric field is changing with time |